在竖直地面上以速度2v0竖直上抛一物体A后，又以初速度v0从同一地点竖直上抛另一物体B，若要使物体在空中相遇，则两物抛出的时间间隔Δt的取值不可能为（不计空气阻力）
We visited a farmer Dick .
— Do you think it is right ? — Yes , .
His son is good collecting stamps .
The map is on the wall their classroom .
My teacher often asks us English as much as possible .
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